Effect of electrochemical parameters on the formation of anodic films on commercially pure titanium by plasma electrolytic oxidation

In this paper the effect of current density and anodizing potential on both surface morphology and internal structure of Ti anodic coatings were studied. Anodic films were obtained in galvanostatic and potentiostatic modes. Anodic films obtained at galvanostatic mode do not show significant changes in surface morphology, exhibiting a porous structure of circular pores. Nevertheless, the anodic films obtained at potentiostatic mode show two different morphologies depending of the potential applied. The chemical composition of the coatings assessed by micro-Raman spectroscopy shows that the coatings are composed mainly of titanium dioxide in anatase phase with presence of some constituents of the anodizing solution as evidenced by EDS. Furthermore, EIS analysis allowed to correlate internal structure changes in the coatings with changes in the electrical parameters of the layers forming the coating.